The present invention relates generally to the field of locks.
Heretofore, it has been known generally from U.S. Pat. Nos. 2,854,839; 3,695,068 and 3,899,906 to provide locking mechanisms of the pivoted or swinging bolt type for mounting in the narrow stile of a door, and the present invention constitutes an improvement over the lock mechanisms disclosed in these patents.
The mechanism in the above-mentioned U.S. Pat. No. 2,854,839 disclosed an early concept in the development of a narrow stile mountable lock of a type which produced features which permitted the obtainment of maximum security. This lock utilized a relatively long main bolt actuating lever which was pivoted at one end and connected at its other end to the lock bolt, the lever mounting a releaseable detent latch between its ends which cooperated with adjacently disposed slots to provide the deadlocking operations of the main bolt. This lock was limited for use with key-actuated lock cylinder assemblies of the casement type, and which are threadedly secured to a side plate of the lock mechanism casing. A notable advantage of the lock mechanism as disclosed in this patent resides in the design arrangement wherein the swingable end of the actuating lever that is connected to the main bolt is in a configuration which permits the bolt-connected end to move symmetrically to positions lying on opposite sides of a center line connecting the pivots of the actuating arm and the main bolt, and thus contribute to a desirable and effective distribution of the operating forces.
In the later U.S. Pat. No. 3,695,068, the operating advantages of the preceding patent have been retained and incorporated into an improved combination locking and latching assembly which is similarly adapted for narrow stile mounting. In the combination locking and latching arrangement of this patent, the latch member is spring-urged to a latched position and is independently operable by a latch handle, knob or the like to an unlatched position, while the locking bolt is arranged to be actuated in a normal manner by a key-actuated cam, the key-actuated cam being further operable, in an unlocked position of the main locking bolt, to move the latch member to a retracted or unlatched position.
Both of these patents, therefore, were limited to the use of the casement type of key-actuated lock cylinder assemblies. At a more recent date, the cam actuator of the insert type was gaining favor in many countries of the world, and the lock mechanism of U.S. Pat. No. 3,899,906 is designed to take advantage of the features of the insert type of cam actuator. In the lock mechanism of this patent, the configuration of the bolt actuating lever was changed to make use of a rocker lever instead of an actuating lever which was pivoted at one end. This change had the manifest advantage of permitting the use of the insert type of cam cylinder assembly, but because of the particular type of releasable latch mechanism for operation by the cam arm, the movement of the end of the rocker arm, which is connected to the swingable bolt, departed somewhat from those of the previous patents in that the arm did not move to limit positions which were symmetrically and substantially equally disposed on opposite sides of a center line connecting the arm and bolt pivots.
In accordance with the features of the present invention, it is proposed to modify the structure of the actuating lever for the main bolt, and utilize a new escapement concept at the end of the rocker arm which is associated with the actuating cam, so that in effect, the end of the rocker arm which is connected to the main bolt will be moved or swung to positions symmetrically disposed on opposite sides of a center line connecting the bolt and actuating lever pivots, during actuation of the main bolt between its unlocked and locked positions. A unique escapement concept, which may be referred to as the "EADS" escapement, has additional advantages over the previous arrangements in that it utilizes an end projecting arm which is engageable by the actuating cam arm during the operation of the locking mechanism. Thus, by utilizing the engagement of two "male" members rather than an arrangement in which the camming arm or single male member must be moved into a recess or the like of a "female" member, it is possible to utilize a variety of camming members which may vary considerably in their dimensions.
Another feature of the present invention resides in the arrangement of an interrelated latching mechanism for operation with the new actuating arm and escapement concept of the present invention.